In ophthalmological treatments and procedures, many typical ophthalmic drug delivery systems encounter difficulties and problems due to physiological conditions of the eye. More specifically, when a liquid ophthalmic formulation is applied to the eye, upon instillation, it is quickly eliminated due to lacrimal secretion and drainage. As a result, only a limited number of ophthalmic drugs can be utilized by patients to achieve efficient treatment; otherwise a frequent administration of concentrated solutions is often required to achieve the desired effects. It naturally follows that increasing the retention time of a liquid ophthalmic formulation after it has been administered is often very desirable. Similarly, the same is desirable for topical drug formulations that are applied to skin of burn patients to relieve the burn symptoms and to accelerate the process of healing or gun-shot victims to seal wound and prevent loss of blood.
In the field of ophthalmology, to lengthen the retention time of instilled drug in the eye and to enhance its bioavailability, various ophthalmic vehicles, such as ointments, aqueous gels, suspensions inserts and implants, have been developed and used. However, these ophthalmic vehicles are not free of flaws and drawbacks. For example, the use of ointments often causes blurred vision. Using inserts caused serious problems due to low patient compliance. Implants require surgical intervention with concomitant risks of infection and inflammation.
Gel forming systems have been especially popular for increasing the pre-corneal retention time and improving bioavailability of the ophthalmic drugs. Typically, such gels comprise thermoreversible polymers that can undergo a rapid liquid-to-gel phase transition once they have been administered to the eye. However, typical in situ gel-forming compositions require the use of high concentrations of polymer to form the gel and therefore typically are not suitable for use in ophthalmic drug delivery.
This patent specification discloses alternative in situ gel-forming compositions that are free of the above described drawbacks and deficiencies making them better suitable for both ophthalmological and burn-healing treatments, and methods of fabricating and administering the same.